Air Conditioner Basics, Tips and Tricks for your Window Units

Window air conditioners are very simple appliances. They operate on the exact same principles as refrigerators, freezers or dehumidifiers.

Air Conditioner Basics - How The Work

All residential window air conditioners have a cooling system made up of four primary components, a compressor, an evaporator, a metering device, and a condenser.
Air conditioner cooling systems are better understood if you think of them as devices that remove warmth from the air rather than cooling the air.
When the unit is running, the circulating fan and compressor are running simultaneously.
The fan motor has tow fan blades attached to it on either end.
The fan blade on the inside part of the air conditioner continually draws room air over the evaporator coils, which are cold.
The fan blade on the outside part of the unit continually draws fresh outside air over the condenser coils, which are warm.
Because the evaporator coils are cold, they cause moisture in the room to collect on them, much like a cup of ice water on a warm, humid day.
When the amount of moisture increases, it begins to drip down off of the coils into the bottom pan of the air conditioner.

Air Conditioner Buying Tips

Cooling Capacity - The ability of an air conditioner to cool an area is measured in BTU/hour. The higher the BTU, the more cooling power the unit has. Don't make the mistake of choosing a model with too much cooling capacity; it will cycle on and off too often, not staying on long enough to remove humidity from the air. Have a rough estimate of the sizes of the rooms you want to cool (in square feet) before you start shopping.
Energy Efficiency - Look for high efficiency air conditioners. Efficiency is measured by the EER (energy efficiency rating), which is displayed on all air conditioners sold in the US. The higher the EER the more efficient the model and the lower your energy bill. A model with an EER of 10 should use about 20% less energy than one with an EER of 8.
Installation Requirements - Make sure that the unit is the right size for the window you plan to mount it in. Protect your back by having enough help to install the air conditioner (most are awkward and very heavy). Some air conditioners require a metal shelf, or special electrical wiring (220 volts).

Tricks to Keep Your Air Conditioner Maintained

Replace or clean the filter every month

Air conditioners are outfitted with a simple electrostatic filter in the front grill area to filter the air that passes through them. If your unit has a filter you should replace/clean it once a month during the cooling season. You can purchase electrostatic cut-to-fit filter material at RepairClinic.com.

Inspect cooling coils for frost or ice build-up

If the temperature outside the room where the air conditioner is placed becomes cool -- approximately 60 degrees Fahrenheit or lower -- check the coils on the front of the air conditioner to be sure they are not icing up. If they are, turn the air conditioner off until the temperature rises. Also, make sure the filter is clean.

Don't short cycle the cooling system

Air conditioners have a cooling system identical to a refrigerator's. It's important not to turn the unit off and then back on right away. Wait at least ten minutes after shutting the unit off to allow pressure in the refrigeration system to equalize once again. This will prolong the life of your air conditioner.

Store the unit in a basement or utility room, not a garage

Mice and other small animals love to nest in air conditioners. Thay can cause serious damage to the unit by chewing on wiring and insulation. Also, wasps and birds like to nest in uncovered units left in windows. Avoid these problems by storing units in a protected area, away from small animals, or by installing a cover on the part of the air conditioner that is outside.

Clean condenser coils annually

Condensing coils on an air conditioner will get very dirty over time. Dirt tends to accumulate on the inside of the coils, out of site. Remove the entire conver of the air conditioner to gain acces to the coils. They can be cleaned by blowing compressed air at them or by using a soft bristle brush to wipe the dirt off. Be sure to also clean any dirt or lint build up in the bottom of the air conditioner so condensate water will be picked up by the condensing fan slinger properly.